Effect of composition and microstructure of humic acid on 3,3 ',4,4 '-tetrachlorobiphenyl sorption
Effect of composition and microstructure of humic acid on 3,3 ',4,4 '-tetrachlorobiphenyl sorption
复制标题
腐植酸组成和微观结构对3,3',4,4'-四氯联苯吸附的影响
DOI：
10.1007/s11356-018-1536-y
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发表时间：
2018
影响因子：
5.8
通讯作者：
Ren Wenjie
中科院分区：
文献类型：
--
作者：
Dai Shixiang;Zhao Ling;Teng Ying;Wang Xiaomi;Ren Wenjie
多氯联苯(PCBS)是一类持久性有机化合物，由于其疏水性强，对土壤有机质(SOM)的吸附/解吸作用显著影响其在土壤中的去向和迁移。腐植酸(HA)是有机质的重要组成部分，不同来源的腐植酸组成和微观结构不稳定，导致其吸附能力不同。因此，本研究考察了羟基磷灰石的组成和微观结构对3，3‘，4，4’-四氯联苯(PCB77)吸附的影响。用傅立叶变换红外光谱(FTIR)和固体碳-13核磁共振(13C-核磁共振)谱分析了PCB77在HAS上的主要吸附机理。元素含量分析表明，不饱和碳(芳香碳、羧基碳和羰基碳的总和)的含量顺序为YHA>；SHA>；AHA。此外，YHA和SHA的颗粒表面非常粗糙和复杂，而AHA的颗粒表面相对光滑，颗粒尺寸均匀且分散。吸附实验结果表明，PCB77在HAS上的吸附容量顺序为YHA>；SHA>；AHA，说明不饱和C的含量控制了PCB77在HAS上的吸附。PCB77在AHA或SHA上的吸附不随背景溶液离子强度的增加而变化，表明PCB77与HAS之间不存在氢键或静电相互作用。红外光谱和~(13)C-核磁共振谱的结果表明，可能的作用机理主要是π-π与HAS之间的共轭作用和疏水结合。
The fate and transport of polychlorinated biphenyls (PCBs), a class of persistent organic compounds, in soils was markedly affected by their sorption/desorption on soil organic matters (SOM) due to high hydrophobicity of PCBs. Humic acid (HA), an important fraction of SOM, has no steady composition and microstructure from different origins, resulting in their diverse sorption capacity. Therefore, the effect of composition and microstructure of HA on sorption of 3,3′,4,4′-tetrachlorobiphenyl (PCB77) was investigated in this study. The primary sorption mechanism of PCB77 on HAs was also demonstrated by using Fourier transform infrared (FTIR) and solid-state carbon-13 nuclear magnetic resonance (13C-NMR) spectroscopy analysis. Elemental content analysis of three HAs showed that the content of unsaturated C (the total of aromatic, carboxylic, and carbonyl carbon) followed an order of YHA>SHA>AHA. Furthermore, YHA and SHA had remarkably rough and complicated particle surfaces but AHA had relatively smooth surface and the well-proportioned and interspersed particle sizes. The results of the sorption experiment showed that the sorption capacity of PCB77 on HAs followed a similar order of YHA>SHA>AHA, indicating the content of unsaturated C of HAs controlled the sorption of PCB77 on HAs. Sorption of PCB77 on either AHA or SHA did not change with increasing ionic strength of background solution, implying that there was no H-bond or electrostatic interaction between PCB77 and HAs. The result of FTIR and13C-NMR spectra showed the primarily possible mechanism was π-π conjugative interaction and hydrophobic binding between PCB77 and HAs.